Journal of the American Helicopter Society (J AM HELICOPTER SOC)
Journal Impact: 1.83*
*This value is calculated using ResearchGate data and is based on average citation counts from work published in this journal. The data used in the calculation may not be exhaustive.
Journal impact history
|2016 Journal impact ||Available summer 2017 |
|2015 Journal impact ||1.83 |
|2014 Journal impact ||2.00 |
|2013 Journal impact ||1.73 |
|2012 Journal impact ||1.79 |
|2011 Journal impact ||1.62 |
|2010 Journal impact ||1.54 |
|2009 Journal impact ||1.21 |
|2008 Journal impact ||1.47 |
|2007 Journal impact ||0.98 |
|2006 Journal impact ||0.63 |
|2005 Journal impact ||0.52 |
|2004 Journal impact ||0.75 |
|2003 Journal impact ||1.00 |
|2002 Journal impact ||0.61 |
|2001 Journal impact ||0.53 |
|2000 Journal impact ||0.65 |
Journal impact over time
|Cited half-life ||>10.0 |
|Immediacy index ||0.23 |
|Eigenfactor ||0.00 |
|Article influence ||0.46 |
|Website || Journal of the American Helicopter Society website |
|Other titles ||Journal of the American Helicopter Society |
|ISSN ||0002-8711 |
|OCLC ||1827576 |
|Material type ||Periodical |
|Document type ||Journal / Magazine / Newspaper |
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Publications in this journal
[Show abstract] [Hide abstract] ABSTRACT: The effect of vortex generators on helicopter drag was investigated in a wind tunnel test. An array of counterrotating vortex generators was mounted on the rear ramp of a heavy-class helicopter model, slightly downstream of the fuselage upsweep.
The wind tunnel campaign also included tests with a radome positioned upstream of the vortex generators to evaluate the robustness of the vortex generators. At cruise angle of attack, a drag reduction of about 2% with respect to the complete helicopter configuration was measured for the baseline fuselage configuration with the vortex generator array installed.
The range of angles of attack and sideslip where the vortex generators were effective for drag reduction was established. The addition of a radome mounted upstream on the fuselage lower side renders the vortex generators ineffective. However, for the model attitudes where the vortex generators were ineffective, the vortex generators did not increase helicopter drag.
Steady and unsteady pressures measured on the fuselage rear ramp revealed the flow behavior due to the presence of the vortex generators.
[Show abstract] [Hide abstract] ABSTRACT: This work developed and verified a computational model to predict self-excited limit cycle yaw oscillation (SELCYO) instability of external sling payloads carried under aircraft with dual-point suspension. Inverted-V and inverted-Y slings during steady-state level flight are discussed. The primary goal was to provide a design tool for comparison of the onset of SELCYO between alternate sling geometries. The computational model incorporates steady-state aerodynamic loading during level flight based on scale-model wind tunnel testing. Scale-model sling tests of the onset of SELCYO in the same wind tunnel were used for validation. Predictions of cargo hook load for a full-size HMMWV-M1025 payload carried by inverted-V slings are compared to V-22 Osprey flight-test data. Predictions of stability indicate that stiffer slings are generally more stable, and inverted-V slings are significantly more stable than inverted-Y slings. Small differences between right and left front sling leg lengths caused by rigging error can significantly reduce stability.
[Show abstract] [Hide abstract] ABSTRACT: The hovering performance and the lifting capability of tiltrotor aircraft are strongly affected by the aerodynamic interaction between wing and rotors. The tiltwing concept represents an interesting technology to increase the hover performance by reducing the wing-rotor interference. The present work investigates the aerodynamic interaction between wing and rotor in hover for a scaled tiltwing aircraft half-span model. A comprehensive experimental campaign, including force measurements and particle image velocimetry surveys, was performed together with computational fluid dynamics simulations. Numerical predictions were validated using experimental data and were used to describe the flow field.
[Show abstract] [Hide abstract] ABSTRACT: Anthropometric test devices (ATDs), commonly referred to as crash test dummies, are effective tools used to conduct aerospace safety evaluations. In this study, the latest finite element (FE) model of the Test Device for Human Occupant Restraint (THOR) dummy was simulated under vertical impact conditions based on data recorded in a series of drop tests conducted at the NASA Langley Research Center (LaRC). The purpose of this study was threefold. The first was to improve and then evaluate this FE model for use in a vertical loading environment through kinematic and kinetic response comparisons. The second was to evaluate dummy injury criteria under variable impact conditions. The last was to determine the response sensitivity of the FE model with respect to its pre-impact postural position. Results demonstrate that the updated FE model performs well under vertical loading and predicts injury criteria values close to those recorded in testing. In the postural sensitivity study, the head injury criteria (HIC) response and peak lumbar load (LL) show to be primarily sensitive to the pre-impact head angle and thorax angle, respectively. The promising results shown by the dummy model recommends its use in impact simulations with vertical deceleration pulses close to those used in this study. In addition, it is believed that assigning accurate viscoelastic material properties to the deformable parts of the model may further increase the model fidelity for a larger range of impacts.
[Show abstract] [Hide abstract] ABSTRACT: This paper presents the development of a 12-degree-of-freedom flight dynamics model for a small-scale unmanned helicopter in both hovering and forward flight. The helicopter was fully instrumented and flight-tested for this modeling work. The development of this detailed model, appropriate
for the design of a high-bandwidth control system, for such a small unmanned helicopter is unique. The model utilizes both detailed physics-based modeling and state-of-the-art parameter identification techniques. The model includes the coupled rotor-body-stabilizer bar dynamics along with
the heave-inflow-coning dynamics. The rotor regressive flapping dynamics and the stabilizer bar dynamics are included within the model using a first-order approximation to the second-order flapping dynamics. The effect of the second-order coning dynamics and inflow dynamics on the heave motion
is also discussed. This modeling process can be extended to model other small-scale unmanned aerial vehicle helicopters.
[Show abstract] [Hide abstract] ABSTRACT: De-icing using piezoelectric actuators is considered as a potential solution to the development of low-energy ice protection systems for rotorcraft. This type of system activates resonant frequencies of a structure using piezoelectric actuators to generate sufficient stress to break the bond between the ice and the substrate. First, a numerical method was validated to assist the design of such systems. Numerical simulations were performed for the case of a flat plate, and validated experimentally. The model was then used to study important design parameters such as actuator positioning and activation strategies and it was concluded that positioning actuators at anti-nodes locations, and activating them in phase with those anti-nodes allowed to obtain maximum displacements for a given vibration mode. The findings were then used to apply piezoelectric de-icing to structures more representative of a helicopter rotor blade. The method was implemented to a thinned Bell 206 main rotor blade and a Bell 206 tail rotor blade. Partial de-icing was demonstrated in an icing wind tunnel. Power input to the actuators was below 12 W/in2 for all structures. Copyright© 2014 by the American Helicopter Society International Inc. All rights reserved.
[Show abstract] [Hide abstract] ABSTRACT: The experimental investigation of constant blowing air jets as fluidic control devices for helicopter dynamic stall control is described. A carbon fiber airfoil of constant OA209 cross section was fitted with a pneumatic system to deliver dry compressed air as jets for flow control at total pressures of up to 10 bar. The experiment used porthole jets of radius 1% chord, positioned at 10% chord and with spacing 6.7% chord. The positive dynamic stall control effects were demonstrated at Mach 0.3, 0.4, and 0.5 for deep dynamic stall test cases with the best test cases reducing the pitching moment peak after the main stall by 83% while increasing the mean lift over one pitching cycle by 30%. The conclusions from the experiments are supported by three-dimensional unsteady Reynolds-averaged Navier–Stokes (URANS) computations of the pitching airfoil with flow control using the DLR-TAU code.
[Show abstract] [Hide abstract] ABSTRACT: New helicopter rotor designs are desired that offer increased efficiency, reduced vibration, and reduced noise. This problem is multidisciplinary, requiring knowledge of structural dynamics, aerodynamics, and aeroacoustics. Designers in industry need methods that allow the most accurate simulation tools available when optimizing designs. Computer simulation and optimization of rotors have been advanced by the development of "comprehensive" rotorcraft analysis tools, performing aeroelastic analysis using Computational Structural Dynamics (CSD). Though useful in optimization, these tools lack built-in high fidelity aerodynamic models. The most accurate rotor simulations utilize Computational Fluid Dynamics (CFD) coupled to the CSD of a comprehensive code, but are generally considered too time consuming where numerous simulations are required like rotor optimization. An approach is needed where high fidelity CFD/CSD simulation can be routinely used in design optimization. This paper documents the development of physics based rotor simulation frameworks. A low fidelity model uses a comprehensive code with simplified aerodynamics. A high fidelity model uses a parallel processor capable CFD/CSD methodology. A synergistic process is developed that uses both frameworks together to build approximate models of important high fidelity metrics as functions of certain design variables. To test this process, a 4-bladed hingeless rotor model is used as a baseline. The design variables investigated include tip geometry and spanwise twist. Approximation models are built for high fidelity metrics related to rotor efficiency and vibration. Optimization using the approximation models found a design having maximum rotor efficiency while constraining vibration. This design is tested in the high fidelity simulation and shown to be a good design, providing evidence that the process has merit. Ultimately, this process can be utilized by industry rotor designers with their existing tools to bring high fidelity analysis into the preliminary design stage of rotors.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.